Traverse mechanism for grinding machines and the like



M. FAIREST April 2451951 IKE TRAVERSE MECHANISM FOR GRINDING MACHINES AND THE L Filed Jan. 27, 1948 2 Sheets-Sheet 1 I nuentor 5M April 24, 1951 v M. FAIREST 2,550,543

TRAVERSE MECHANISM FOR GRINDING MACHINES AND THE LIKE Filed Jan. 27, 1948 2 Sheets-Sheet 2 Has.

l50w- I 66 Inventor F 'T- 52 L1, L: y

CUM Q05 Mala? Atlorney Patented Apr. 24, 1951 TRAVERSE ,MECHANISM'FOR GRINDING MACHINES AND THELIKE Morgan Fairest,

'Shefiield, England, .assignor to Morgan Fairest Limited, Sheffield, England ApplicationJanuary 27, 1948, Serial No. 4,513 In Great-Britain January 27, 1947 '8'Claims.

i 'This invention relates to traverse mechanisms for grinding machines and the like, and has particular reference to traversing the work slides in machines for grinding the blades of table knives,

carving knives, garden: and other shears, scissors,

and similar articles of cutlery, although theinvention is also applicable to such purposes as traverse mechanisms forsurface grinders, millers, planers, plano-millers, plano-grindersand sliding and surfacingtraverses of lathes.

In grinding cutlery, it is usual to grind the face (or, in the case of'tableand similar knives, both faces in turn) as an operation in which the blade is rapidly fed idly in an inwardlyoblique. direction across one side of a-cuprwheel, theface .of which is hollow to form a conical surface to im part the desired slightly rounded face to the face of the blade; the blade is thenqmoved into contact with the wheel, given a dwell while the wheel grinds the neck of the blank adjacent the bolster to the required amount; and then withdrawn outwardly slowly still in contact with the face of the wheel until the blade tip has been ground, the blade being rocked during withdrawal to adjust the taper of. the blade to the lessening thickness of the blade from bolster to tip.

One object of thepresent vention is to enable the speed of the inward and outward strokes and the length ofany .desireddwellv to be'quickly and simply adjusted. Another object is to enable the outward stroketo becompleted or, if desired, repeated at a speed independentof thenormal speed at which this strokexis carried out; and also to interrupt and reverse the inward stroke at any point if required.

Accordingto; the present invention, the traverse mechanism comprises. a traversing work support, stops adapted .to limit the traverse, hydraulic means for effecting the traverse in both directions, a reversin valve mechanism for admitting fluid to the hydraulicmeans to effect the traverse stroke in each direction in turn, and pressureresponsive means to which fluid is also admitted during at leasta traverse stroke in one direction, the pressure-responsive means being adapted to actuate the valve mechanism atthe end of that stroke by the build-up cf pressure in the fluid when the work support reaches the stop at the end of thatstroke, thereby reversing the direction of traverse oithe work support.

The reversal ofthe Work-support traverse being effected by the build-upof pressure in the operating fluid circuit as the work-support reaches 0116101 other offthels-tops, the length of the workvsupport; stroke isyindependent of the responsive reversing means as,

full length of the stroke of the hydraulicmeans and may be varied byadjustment' of theposition of the stops up to the full limit of that stroke.

Thebuild-up. of pressure in'the pressure-responsive means may bedelayed by the introduction of a needle or other throttle valve in the fluid circuit to the. pressure-responsive means, to provide a dwell after the work-support reaches thestop at theaendzof its strokebeforethetraverse is reversed. The throttle valve may be adjustable to vary the length of the dwell;

A flow-control valve may be incorporated the fluid circuit-1 for-at least one direction of traverse to permit a variation-in the speedat which that traverse stroke is effected. Manually-controlled means wmaybeprovided to by-pass awfiow control valve to permit the stroke to be'efiected ata greaterspeed than when the valve is in operation, -and-such means may also be adaptedstoibe brought -i-nto-operationatany stage in the previous stroke so as to reverse that stroke independently of the pressure-responsive means, normally' used to effect reversaLand to'completethe first: stroke atzthegreater speed.

The reversing valve is preferably incorporated in a single valve unit, being automatically r versed between the strokes by the =pressure-re sponsive means also incorporated in the valve unit. The-reversing valve may be manually controlled to initiate the; movement of theworksupport and such :manual .-control preferably serves also to-efiect the Joy-passing of the flowcontrol. valve-:as mentioned above;

The I pressure-responsive means may comprise a hydraulic "cylinder, a piston of which "positively effectsreversal of the reversing valve-onthe build-up of pressure in the cylinder. The invention; thus ofiers-a verysimplecontrol unit; the single valve unit-in which isecombined the, re.- versing-cylinder and a single manual, control member. The-- needle throttle valve and -flowcontrol valve may also be advantageously combined in the unit.

The hydraulic means for -effecting the traverse of the worksupport may comprise-a single cylinder to ports at the opposite ends of -.Which ,the fluid is admitted in turn to urge the workr-support infirst'one-directionand thenthe other, or separate cylinders. maybe-used toeffect the .tw,o strokes.

The invention also comprises hydraulic 1 re.- versing valve .mechanism embodying pressuredescribed above, particularly ofthe piston-and-cylindertype, to gether, if desired, with one. or more of the. auxiliary features: throttle-valve, flow-control valve, by-pass means, also described above, manuallycontrolled means, and unit construction.

One form of hydraulic traverse mechanism will now be described in greater detail as applied to the traversing of a work support in a cutlery grinding machine, although the traverse mechanism to be described is also applicable to other machines as previously mentioned. In the accompanying drawings:

Figure 1 is a plan view, partly in section, of a grinding machine set for the grinding of table and similar knives;

Figure 2 is a front elevation of the machine, partly in section on the line 22 of Figure 1;

Figure 3 is an end elevation of the machine on the line 3-3 of Figure 2;

Figure 4 is a diagram showing the approach of the blank to the grinding wheel;

Figure 5 is a section on the line 5-5 of Figure 2, on an enlarged scale;

Figure 6 is a section on the line Ii6 of Figure 5;

Figures 7, 8, and 9, are sections on the lines 1-1, 88 and 9-9 respectively of Figure 6; and

Figures 10 and 11 are views similar to Figure 6 at difierent stages in the operation of the machine.

The grinding machine embodies a work-support of the type fully described in Patent No. 2,481,918, dated September 13, 1949, and, referring in the first instance to Figures 1, 2 and 3, comprises a table I ll mounted on slide ways II (Figure 3) carried by a bed-plate I2 resting on the machine bed I3, so as to be movable to and fro in a direction generally transverse to the axis I4 ofa cup wheel I5.

A work slide I6 is carried on the upper face of the table II], and to it is secured an angle bracket I1, from which pivot brackets I 8 protrude towards the wheel I5 to receive pivot pins I9 at each end of a work support 29 comprising a long block to the face of which is secured a pad 2! which supports a knife blade 22 to be ground. An arm 23 of the work support carries a roller 24 resting on a former bar 25 to rock the support about the pivot pins I9 as the support is carried by the table It) across the face of the wheel I5, so as to rock the blade 22 gradually as grinding proceeds from neck to tip, of the blade arising from the gradual thinning of the back edge of the blade in the direction of the tip. The former bar is adjustable about a pivot 26 (Figure 3) on a mounting 21 by a setting screw .28, out of line with the pivot 26, and is clamped in adjusted position by a bolt 29, The mounting 21 is slidable vertically on a support bracket 30 upstanding from the bed-plate I2 and is adjustable for height by a screw 3!.

The axis I 4 of the cup wheel I5 is shown inclined (at about 10) to the normal to the path of the table I I], and the face 32 of the wheel is inclined inwards to the same amount so as to lie parallel to the path of the table, the movement of the the left-hand side 33 of the wheel, with an idle movement in one direction (to the right in Figures 1 and 2) and a grinding movement in the reverse direction. The inward inclination of the face 32 of the wheel produces the desired slight outward curvature on the ground face of the blade 22. The machine may, however, be constructed with the table and work-holder reversed with respect to the wheel, in which case the work is carried across the right-hand side of the Wheel,

to allow for the varying taper 5" table II] carrying the blade 22 across I to enable the other side of the blade blank to be ground; and, in fact, machines are generally used in pairs, one left-hand and one right hand.

For some purposes (the grinding of plane or hollow-ground (e. g. shear-blade) surfaces), the axis M of the wheel may be normal to or inclined in the opposite direction to the normal to the path of the table I9, and adjustment of the relative inclination is provided for by pivoting the bed-plate I2 carrying the table In about a pin 34 screwing into the machine bed I3, the axis of the pivot pin lying vertically beneath the operative left-hand portion 33 of the wheel. The plate I2 is secured in adjusted position by a bolt 35 near the pivot pin 34 and two bolts 36 adjacent the front and left-hand edges of the plate, the bolts 34, 35 passing through slots 31, 38 in the plate I2 and screwing into the machine bed I3.

The slide I6 is mounted on slideways 35 carried by the table Ill, the slideways running at from right to left from the front to the back of the table and the slide It being held to the table II) by washers 4| retained by lock nuts 42 on pins 43 projecting from the table I5 and passing through slots 45 in the slide parallel to the slideways 45. A plunger 45, carried b the slide I8 and also parallel to the slideways, is urged by a spring 56 into contact with an abutment 41 protruding from the table I5, so as to urge the slide 86 towards the front of the table.

A hydraulic cylinder 18 carried by the plate I2 between the slideways II for the table ii] runs parallel to the length of the table and the piston 49 is connected by a piston rod 49A to a lug 50 depending from the right-hand end of the table I0. Pressure oil admitted to one or other of ports 48A, 48B of the hydraulic cylinder 48 in turn, through flexible pipes 5IA, 5IB connected to a multi-way valve unit 52 (as will be described in detail later), causes the table Iii to move to and fro with any desired length of stroke.

Running lengthwise of the table I0 is a parallel slot 53, passing to the right-hand end of the table and breaking through a recess 56 near the middle of the table. A push-rod 55 closely fits the slot and a lateral arm 56 of the rod protrudes through the recess 54 beyond the front of the table. Opposite the arm 56, the rod is notched at 51 to form a land 58 leading by a cam slope 55 to the edge SE! of the rod. A follower roller 6! carried by the slide I5 depends into the recess 55 and is urged by the plunger 45 into contact with the rod 55.

The end of the rod 55 projects beyond the end of the table i5 and carries a plate 55A facing an. adjustable stop 62 on a bracket 63 upstanding from the bed-plate I2. The plate 55A itself carries an adjustable stop 64 facing the edge of a cover plate 65 secured at the end of the table I5 over the push-rod 55. An adjustable stop 55 carried by a bracket 61 upstanding from the foot of the front slide-way I I lies parallel to the length of the table It in line with the outer end of the lateral arm 55 of the rod 55.

In Figures 1 and 2, the table I0 is moving on its idle stroke to the right under the admission of oil through the left-hand port 48A of the hydraulic cylinder 58. The follower roller GI bears on the land 55 in the notch 51 of the push-rod 55, the slide It thus lying in its nearest position to the front of the table In. In this position the lade 22 lies clear of the wheel I5, as shown.

As the table I8 nears the right-hand end of its stroke the plate 55A on the end of the push-rod .asso aes .55*meets:the. stop- 62 (the actual position shown in Figuresl and2) ,and the push-rod is prevented from further motion to the right. The table id continuing its; motion-tothe right, the. follower roller 6! is caused to ride up the cam slope 59 of the now-stationary r-od: and on to the edge of the rod.

The slide I6 carrying the roller 6| is forced to follow the movement of the roller, and is thus pushed towards the rear of the table II], by an amount equal to the lift of the cam, to bring the blade 22 into-grinding contact with the wheel. I5; the .slide moving. along theinclined slideways 40. During this movementthe spring M is compressed on to the plunger 45.

Onreaching the 'full lift of the camj slope 5i the follower-roller 6| comes to rest-on theedge 60 :of the rod 55, andremains'urged against-the rod by the pressure of the'plunger 45, the whole length of the rod resting. in'the slot 53 providing 'a rigid: backing against the thrust of the slide Ililaterally' of the table IE.

When the cover plate reaches the stop 64, the right-hand motion of the table It ceases (as wilbe described later) and at this moment the :outside diameter of the wheel I5 makes grinding contact at the neck of the blade 22, i. e. against the'bolster 68 (Figure 4), the blade having been brought against the face of the wheel by the movement of the slide IE to the rear of the table I55; The operation of the hydraulic cylinder 48 now reverses (as will be described later) and the table II] moves to the left, carrying with it the slide I'Ei, which is locked to the table by the pressure of the'follower roller IiI on the edge 43% of the rod'55.

The movement of the work up to this point may be closely followed by reference to Figured:

The blank (blade 22, bolster 68) as shown in full lines is moving to the right (arrow a) as in Figures 1 and 2, with the blade 22'paral1el to, but clear of, the face 32 at the left-hand side 33 of the Wheel I5.

When the push-rod 55 is held by encountering the stop 62, the table It continues to move by the amount shown by the chain-line containing the arrow 1;, and the cam 59 pushes the slide I6 (and therefore the blank) in a 45, direction as shown by the chain-line containing the arrow c. The component of the table movement and l the slide movement is thus a movement along the chain-line containing the arrow d.

The blank has now reached the position shown in broken lines (22%6B the blade 22 having one side in contact with the face 32 of the wheel,

and the neck 58 lying against the radiused edge iii of the wheel. At this point, the table it is reversed by the hydraulic cylinder 48 (arrow e), and grinding of the side of the blade 22* continues from the completed neck to the tip of theblade.

During the grinding stroke, the pressure of the wheel keeps the rear side of the blade firmly against the pad 2 l. The accurate guiding of the table Ill by the slide'ways I l and the pressure of the spring 66 through the slide I5 to the long edge of the slot 53 containing the push-rod 55 ensures that the blade follows an accurate line across the wheel i5, which may be repeated. with equal accuracy if itprov'es necessary to send the blade a further time across the wheel. As a resuit, a highly finished ground surface isproduced that calls for the minimum amount of glazing in a subsequent operation, as is usual withtable and similar knives.

When. the tiprof the blade 22 reachesthe' face 3220f the "wheel; the stop 66 meetsthe arm -56 to push-the 1Oda-55 tothe right (relatively tothe moving table I0), thus carrying the cam-slope 591under the follower roller BI. The-pressure of the plunger causes the roller-5l to pushthe rod1l=-55-to theright (there being nothing to oppose this movement of the rod), and the roller 6| reaches the land 58 with a snap action. The slide ['61131'1118" moves quickly towards the front of the table I-IL-and the blade. 22 is-withdrawn from the wheel, with no delayed contact that might mar theground surface of the tip of the blade.

The. left-hand motion of the table Iilcontinues until thearm 56 of the rod55, which has been displaced :to the right-hand end of the recess 54 'assthe.rollervfiisreaches the land 58, again contacts the stop-:66, when the motion ceases (as willibe described later). The ground blade is now removed andreplaced by a fresh blanlgxor, if necessary, the blade is left to undergo a further grinding -.cycle.. Reversal of the operation of the cylinder 48. (as-will be described later) again brings the mechanism'to the position shown in Figures 1 and 2. The width of the recess Bl provides the necessary freedom of movement of the arm'56 relative to the table IE3. The three stops 62,154 and 66 enable the positions of the'ends of the strokes and. the rearward and forward movements of the slide I5 to be determined with precision in accordance with'the length of the blade 22, in conjunction with the valve mechanism for the supply of oil to the cylinder "48 as will now be described.

The valve unit 52 (Figures 5 to111) comprises a valve piston III which is hardened, ground and lapped into-a valve bore II of av main rectangular block 12 mounted by bolts TZA on the back of a panel ISA secured to the front of the machine bed I3 (Figure 2) by bolts 53B. The piston IE1 is circumferenti-ally grooved at 13, M, I5 and 16,. the grooves I3, M and I6 being in communication with each other through holes I! drilled radially from the bottoms of the grooves into a bore 18 (Figure 7) drilled axially in the piston from its right-hand end I9, the open end of the bore I8 being closed by a screwed plug 8!]. A piston rod 8| extends from the left-hand end of the piston through a bush 82 in an end plate 83 bolted to the block I2 by bolts 84, the end plate 83 being formed with a short spigot ilfiengaging the end of the valve bore I I.

The right-hand end of the valve bore II is closed by an intermediate block 85 spigoted at 81 tofit the valve bore and bored at 88 axially with the valve bore H to receive a piston '89 which is an easy fit within the bore 88. The inner end of the piston 89 is rounded at 9B and the outer end is provided with a cup washer Ell closely fitting the bore 88. The cup washer is secured to the piston by a nut 92 on a rod 93 screwed into the end of the piston. The pistonrod 93 projects into a recess 94 in the inner face of an end plate 95 spigotedat 9-3 to fit a counterbore of the piston bore 88. The end plate 55 and intermediate block 86 are secured to the main block 'IZ'by bolts 91.

The Valve bore ii of the main block I2 has circumferential grooves I80, IBI, I02, I53 and W5, thegrooves I00, I03 being connected by the fiexi ble pipes '5IA, 523 to the ports 3 3A, 4813 'respectively of the hydraulic cylinder 18, unions at the ends of the pipe engaging threaded recesses I05, IIIBAdrilledfrom the top face of the block 12 and breaking into the grooves I00; I03.

the pump direct to the tank, as will be described later.

' Two holes III], III are drilled from the bottom face of the block I2 into the valve bore grooves I00,

IOI, the holes breaking through a bore I I2 drilled at right angles to the holes from the front face of the block, and the lower ends of the two holes being closed by screwed plugs I IOA, IIIA.

A circumferentially-grooved cylinder II3 (Figures 6 and 9) rotatably fits the bore II 2, being lapped in position and being retained by square end plates H4, H secured by bolts H6, H1 to the front and rear faces respectively of the block I2, the inner faces of the end plates being formed with spigots II4A, II5A engaging the ends of the bore II2. A shank I I3A extending from the front end of the cylinder II3 passes through a bore II 43 of the front end plate II 4 and projects beyond the latter to receive a cap H8 provided with a short control lever NBA. The end plate I I4 is thick enough to provide a, good length of bearing for the shank II3A in the bore IIIB, the'en'd plate projecting through a square aperture I3C cut in the panel I3A.

In line with the two holes II (I, I I I, the cylinder I I3 is cut away at I I9 to form the eccentric crosssection as shown in Figure 6, which in conjunction with the bore I I2 forms a flow-control valve, the action of which will be described later.

A hole I drilled from the right-hand end of the block 12 parallel to the valve bore II breaks into the hole II I just above the bore IIZ, and its outer end opens into a short groove I'2I cut in the inner face of the intermediate block 86 at right angles to the hole I20.

Two parallel holes I 22, I23 are drilled from the bottom face of the end plate 95 and open into the recess 94 (Figure 8). The rearmost hole I23 is counterbored at I24 to receive a ball I25 urged against the seating provided by the end of the counterbore by a spring I25 retained in position by a screwed plug I21 sealing the lower end of the counterbore, the ball I25 forming an escape valve for oil in the recess 94 as will be described later. The lower end of the hole I22 is sealed by a screwed plug I28.

A hole I29 drilled from the front face of the end plate 95 at right-angles to the two holes I22, I23 intersects the hole I22 and the counterbore I24 and extends slightly beyond the latter to break into a hole I30 drilled from the base of the groove I2I in the inner face of the end plate 95. The hole I29 is counterbored at I 3| from the front face of the end plate 95 to the hole I22, the end of the counterbore being tapered down at I 32 to the diameter of the hole I29 to form a seating for a tapered needle valve I33. The needle valve I33 is carried on the end of a screwed stem I34 threaded into the counterbore I 3I and projecting through a hole I35 in the panel I3A to the front of the machine bed I3. The outer end of the stem I34 is formed with a saw cut I36 for screwdriver adjustment of the needle valve and a lock nut I 37 on the stem serves to secure the needle valve in adjusted position. A protective cap I38 screws on to the projecting end of the stem I34. The needle valve I33 serves as the throttle valve to effect a dwell 8 at the end of the idle stroke of the table I!) before the working stroke is commenced, as will be described later.

A control lever I40 (Figures 2 and 5 and also shown in chain-line in Figures 6, 10 and 11) at the front of the machine is secured adjacent its lower end to the front end of a pivot pin I II mounted in an integral pivot boss I42 of the panel I3A lined with a bush I43. Secured to the rear end of the pivot pin MI is an upwardly extending forked lever I03, the two arms I45 of which carry studs H36 engaging a groove III! (also Figure 6) in a cylindrical head I 58 secured to the outer end of the rod SI of the valve piston 70. The lower end of the lever I II! is formed with a chisel point I09 normally engaging a V-shaped notch I59 cut across the upper end of a plunger I5! vertically slidable in a mounting I52 secured to the panel I3A. The plunger IISI is bored at I53 from its lower end to receive a spring I54 held in compression by an adjusting bolt I55 screwed through the bottom of the mounting I52 and provided with a look not I56.

The normal vertical position of the control lever I33 is as shown chain-dotted in Figure 10. and in this position the table It is at the end of its left-hand motion with the work slide I5 withdrawn away from the wheel I5 and with the arm 56 of the push-rod 55 abutting the righthand side of the recess 59 and the stop 65. To start the table IE on its idle stroke to carry the knife blade 22 to the wheel I5, the control-lever is swung to the right (the position as shown in Figures 2 and 6) thus urging the valve piston I0 to the right-hand end of the valve bore II as shown in Figure 6. The control lever is held in this position by the upward thrust of the spring plunger I 5!, the chisel pointed end I 39 of the lever having travelled up the V-shaped notch I59 of the plunger and come to rest with its face I 57 engaging an inclined face I58 (Figure 6) at the upper end of the notch.

In this position of the valve piston 16, the piston groove I4 uncovers the valve bore grooves IIII, I02 and admits oil under pressure from the pump (via the pipe I38) into the axial. bore l8 of the piston through the radial holes I? in the piston groove and the oil is fed along the bore 78 into the piston groove I3 which uncovers the valve bore groove I00 thus completing the path of the oil to the left-hand port 40A of the hydraulic cylinder 38 through the pipe BIA. Oil is also admitted through the holes III, I20, the grooves IZI, the holes I30, I29, the needle valve I 33 and the hole I22 into the recess 94 in the end plate behind the piston 89.

The valve piston groove I5 uncovers the valve bore grooves I93, I34, thus connecting the righthand port 48B of the hydraulic cylinder 48, through the pipe 5IB, to the tank, via the pipe I09, to complete the return circuit for the oil at the right-hand side of the piston 49.

When the cover plate 65 contacts the stop 64 (as previously described), further movement of the table II) to the right is prevented and pressure builds up in the input oil circuit, which as previously described is tapped through the adjustable needle valve I33 to the recess 95 behind the piston 89. (The latter has, on movement of the control lever I40 to the right, been pushed within the bore 38 (as shown in Figure 6) by the end 19 of the valve piston I0, the piston rod 93 projecting into the recess 94 preventing further adventitious movement of the piston 89 which attests might otherwise bring the cup washer" 9 I war of the bore 88?) y When the pressure" in" the"recess"9fl*has' built" up"to"apredeterminedivalue; the axia'lforce on the piston 89 is sufficient to overcome the re sistance of the spring plunger I51 I holding the control lever H0 inits'right-hand positionand thevalVe piston- I0 is pushed bythe piston-'89"- along'the valve bore-l I" to the position shown in Figure where it-"isheld by th'e chisel point 10 I 49' -of-- the control lever engaging the notch I 5Q in the spring plunger, the spring plungeritself ensuring a quick snap-over to-this "position once the chisel "point I 49 1 of the control lever has been forced by action of the iais'to-ntt over-the crest= of the inclined face-i-fifl- -of the "spring plunger.

The upward pressure of the spring plunger onthe control lever isadj-usted by the adjusting" bolt- I 55 sc that in the positien of the lever in Figure 6 therrormal Working-pressure or the oil in-tne recess -94 during idle strokeof the table- HI is not suffibient to 'di'splacethe valve piston "10;- and the time taken, from-theend of the-right hand motion-of thetable I 0, for the-pressure the recess St -to build up suficiently' to di-splace the valve piston-is determined by adjustment or the needle -throttlevalve I33. Thus, adwell may be provided after the blade -22-hasbeen presented to the whe'e1 I4- (as previous1y-described). I to ensure satisfactory I grinding of the; neck"-Ii3' of the blade beforethe-motion= of the table I ll is reversed to effect the grihding' of l the 'faGe -Of the blade;

When the valve piston I!l*-ispushed by the piston 89 to the position sh'own Figure '1 0}thevalve piston g roove 'm now uncovers 'the' valve bore grooves I92, 103, thusconnecting the -011 under pressurefronr thepumpdirect to the right hand-port 48B of the hydraulic cylinder -{48-, 40 through the pipe 513; to urge' the' ta'ble HP re the left :on its grinding stroke.

The valve bore" gr o0ve= I60 iscovered b'yth valve piston I0 so: that 'the-ohlyoutlet fio this groove-:for" the oilon-the left hand side pistonf wt returning" to the tank through the L 5IA ishalong the hole IIEI- leadingto the-fie control ivalve I I9. The oiI-passes: into the-flow control :valve'bore' I I2 and-along the hole" I I I--'to'- the valve bore groove It" whichis-no w. ne covered by the piston groove 14 The' oil 'passes throughw the radial holes I1 into -the -a xial bore I3: of the piston and:v alongthe: latter to-the piston groove i6, .whichlnovv uncovers the valvebore groove I04, thustcompleting the return eircuit for the oiltorthe tank through the-pipe I09;

The flow co-ntrol valve governs the return flow of the oil :to' the: tank and so governs: thesp'eedof the grinding strokeof thetable I0 to the left, thus enablingthis grinding stroke to be effected at any desired slower rate than the previous idle stroke of the table, which being effected-at the maximum fluid delivery of. the pump rapidly rnovesthe blade to be ground inwardly and' 'idly across the-face of the grinding wheel. Th'e'flow 65 control valve is shown in Figures"6,:9', 10am 11 at its zero setting, i. e. withthevalve-eccentric' IIQ turned (by the lever II8A) toa position in which it seals-completely the'entra-nce of the bore Ill] into the valvenbore IIZ. When the valveis" turned-to the: position shown in chain-dottedlinesin Figure -6,- it is atsits-maximum flow: set ting: whenthe'speed'iof the grinding lstroke'of the table I 0 I is effected at' the same rate :as the idle stroke. I

The'bore I2 0 leadingfrom" the recess 94 opens into the bore III leading"from the'fi'ow control valve so that-the pressure oftheoil in the recess fall's when thepiston 89 has "pushed the valve iston late the"reversingposition;

When the grinding *strokeis completed andthe arm 5'5 of the push-rod "55 'isfdrced"a gainst'the" stop 66 (as previously described), pressure builds up in the 'oil"'passing from the pump to the hy"-' draulic cylinder 48 and 'the'-oi1 is "passed' from the pump direct-to the tank by the relief valve 595A. The relief valve I08A does not"operate until the pressurednthe oil"has'built"up' to a" value greater than that requiredtooperate the" piston 89at the-end ofth'e idle" stroke. If the blade is satisfactorily ground; another blank is inserted in positionon'the pad 21, and the cycle is repeated by again swinging thecontrol lever' I A? to the right, i. e; to the "position'shown-in' Figure'G.

In swingingthecontroi lever tothe'right-to' initiate a further idle stroke; the" piston- 8911' is" forced back within the bore-88' by the'valve piston it "and the oil in therecess 94" behind the piston" is rapidly ejected from the reces's'along'the hole I 2 3 as the pressure in the oil builds up sufficiently to displace the e'scape-valveball'l'fi against the" resistance of the'spring I261 The throttlevalve I33 "is thus by p'asse'dand"the'oil passes along the valve bore groove -I'Il I; During the initial part' of the movement of the'pontrol 'leverto'therighti the groove IIiI' is 'still"'connected"to the tank" through the piston groove"; axial borel s'fpiston" groove Iii and valve boregroove It' l; soth'atoil' from the recess"94isfedto thetank. During" the latter part'of the'movement'of the lever how? ever thegro'ove Ill'I iscon'nected to wevawetoregroove" I92 (as the valve "piston groove I4 un covers the latter) and" therefore to'the pump; and'the oil from the recess '94 is fed'intdth'e oil from thepuinp'," the pressurebein'g greater" than that of the oil from thepinnp;

The pressure of the oilin th'e"'re"cess"'94required to"operatethe escapeWaive I25 is'greater than the pressure requiredto reverse thevalve" piston 'I0"'(as'previously described), so thatno leakage occurs" through the escapc=valve as the."

pressure in the recess 94"buildsupat"the endof' the idle stroke.

If, during the grindingstroke of thetable" I0; or at the-end of'the stroke, it "is'desi'red to with draw the blade being'groundrapidly from the wheel, the control lever I40 is swungto the lft With thecohtrol iever' h'eld to thelef-t; the'va'lva piston nis earned ta taeaetreae er the valve groove 'lfi- -s'ti ene'ove'rsthe vawbereemvs I52, iflegltliusre'tainiri-g thedirect pump corine tion to the right-hand port-4813 61" the hydrauliccyli'r'ider 43', but-in which the I return circuit T6)? the oil from the left-hand port- ItBA through the pipe el A Icy-passes the flow cohtrol I valve the-oil" passin directly irlto the piston groove whichnowluncover's the valve b'bregr'obv'e i? through tne radi'ar noies me the axial screw-r of the piston, along 'theb ore- '18 to"-the--- pist 1r groove 1-6 "which now uncovers the valve bore 11 groove I06, thus completing the return circuit to the tank through the pipe N19.

'The outward stroke is thus completed at a greater speed than the normal working stroke with the control lever in its central position and the flow-control valve in operation. This bypassing of the flow-control valve may be used to eiiect a rapid completion of the Working stroke once the blade 22 has been fully ground, i. e. when thearm 56 of the push-rod 55 first meets the stop 66 to effect the withdrawal of the blade from the wheel, so that the blade may be quickly removed and replaced by another blank. If desired the rapid left-hand motion of the table It may be used for efiecting a second (generally light) passage of a ground blade across the wheel if this is needed, the control lever being first swung to the right to eifect the idle inward stroke as previously described, and then, after it has been returned to its central position by the reversing plunger 89, being swung to the left to efiect a rapid grinding stroke.

Since the control lever may be swung to the left at any stage in the cycle of the table iii, the latter may be readily brought back rapidly to its normal position, if, for example, the blank is seen to be in wrong position on the pad H, before the idle stroke would normally have been completed and the blank presented to the wheel.

Any oil leaking to the left-hand side of the valve piston during the operation of the machine is returned to the tank via a bleed hole I66 (Figures 6, 10 and 11) drilled in the end plate 83, the bleed hole running into a screwed recess IE! in the bottom face of the end plate to receive the union at the end of a pipe I62 leading to the tank. Any leakage to the right-hand side of the valve piston is forced along the bore 88 (the piston 89 being a free-fit in the bore as previously described), past the cup-washer 9| and into the recess 94 when the control lever is swung to the right to initiate an idle stroke of the table (as previously described).

The hydraulically-controlled traverse mechanism as described produces a high-quality finish to the ground surfaces of the blade, with consequent advantage at the glazing stage to which many blades are next subjected. In addition, the simple adjustment of feed rate and length of dwell at the end of the idle stroke to accord precisely with the size and type of blank to be ground assists in imparting a good finish, as well as conducing to high output.

What I claim is:

1. A hydraulic traverse mechanism for worksupports in grinding and other machines, coniprising a traversing work-support, hydraulic means for efiecting the traverse in both directions, pressure-responsive means, a reversing valve connected to the hydraulic means and the presssure-responsive means, a stop for positively V limiting a traverse stroke in one direction whereby when the stop is encounted pressure build-up in the hydraulic means actuates the pressureresponsive means to operate the reversing valve to bring about a stroke of the work-support in the other direction, and manual means for moving the reversing valve in one direction to initiate a traverse stroke that is automatically reversed by the operation of the pressure-responsive means at the end of that stroke, said manual means also being adapted to move the reversing valve in the opposite direction to produce a reverse stroke independently of the pressure-responsive means.

2. A traverse mechanism as in claim 1, comprising a throttle valve between the reversing valve and the pressure-responsive means to delay the response of the latter to the build up of pressure, thereby producing a dwell before commencement of the reverse stroke.

3. A traverse mechanism as in claim 1, comprising a flow-control valve to reduce the speed of the traverse stroke efiected by operation of the pressure-responsive means, and a by-pass to out out the flow-control valve in a stroke in the same direction efieoted by operation of the manual means.

4. A traverse mechanism for work-supports in grinding and other machines, comprising a traversing work-support, stops adapted to limit the traverse, hydraulic means for effectin the traverse in both directions, a unitary reversing valve structure for admitting fluid to the hydraulic means to efiect a traverse stroke in each direction in turn, said valve structure including a valve cylinder with an inlet port receiving pressure fluid, two outlet ports connected respectively to pressure and exhaust conduits leading to said hydraulic means and an exhaust port, a piston valve movable in the cylinder so as to put the inlet port in connection with one outlet port and the other outlet port in connection with the exhaust port, pressure-responsive means in connection with one of the outlet ports, and comprising a cylinder coaxial with the reversing valve cylinder and a piston slidable so as to operate the piston valve on build-up of pressure, to produce a reversing movement of the valve on build-up of pressure in the circuit to which that outlet port is connected thereby reversing the direction of movement of the hydraulic means.

5. A traverse mechanism according to claim 4, wherein the reversing valve structure also includes a throttle valve between the pressureresponsive means and the outlet port to which the latter is connected, so as to control the rate of build-up of pressure thereby provide a dwell before the reversal of the piston valve.

6. Hydraulic reversing valve mechanism comprising a valve cylinder with an inlet port, two outlet ports, and an exhaust port, a piston valve movable in the cylinder to put the inlet port in communication with one outlet port and the other outlet port in communication with the exhaust port, pressure-responsive means comprising a cylinder coaxial with the reversing valve cylinder and a piston connected to the piston valve, said means being connected to one outlet port was to subject the piston to build-up of pressure in the circuit to which that outlet port is connected, thereby operating the reversing valve.

'7. Hydraulic reversin valve mechanism as in claim 6, comprising manual means for operating the reversingpiston valve in a direction opposite to its operation by the pressure-responsive means, and means for holding the manual means after its operation of the reversing piston valve, the pressure-responsive means operating to overcome the holding means when build-up of pressure effects reversing of the reversing piston valve.

8. Hydraulic reversing valve mechanism comprising a valve cylinder with an inlet port, two outlet ports, and an exhaust port, a piston valve movable in the cylinder so as to put the inlet port in communication with one outlet port and the other outlet port in communication with the exhaust port, and pressure-responsive means in communication with one of the outlet ports, said means being connected to the piston valve to produce a reversing movement of the valve on i3 build-up of pressure in the circuit to which that outlet port is connected, manually-controlled means for operating the piston valve by a movement in one direction, means for holding the manually-controlled means in one position after its operation of the piston valve, the pressureresponsive means operating to overcome the holding means under build-up of pressure, a flowcontrol valve connected to one of the outlet ports to reduce the delivery of hydraulic fluid through that port, and a by-pass for the flow-control valve, the manually-controlled means being movable to another position to. operate the by-pass and increase the delivery of hydraulic fluid;

MORGAN FAIREST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Proctor July 31, 1945 

